JP2006522476A - Vision system and method for calibrating a wafer carrying robot - Google Patents

Abstract

A vision system and method for calibrating the motion of a robot located in a processing system is provided. In one embodiment, a vision system for a processing system includes a camera positioned in the processing system and a calibration wafer. The camera is positioned on the robot and is adapted to obtain image data of the calibration wafer located at a predetermined location within the processing system. The motion of the robot is calibrated using the image data.

Description

Cross-reference of related applications

  [0001] This application is a continuation-in-part of co-pending US application Ser. No. 10 / 126,493, filed Apr. 19, 2002, which is incorporated herein by reference in its entirety.

Disclosure background

Field of Invention
[0002] Embodiments of the present invention generally relate to a vision system, a method for inspecting a processing system, and a method for determining the position of an object in a processing system.

Background of the Invention
[0003] The use of robots in automated processing systems is becoming increasingly popular. Robots can often perform repetitive tasks with accuracy and efficiency that is generally not achievable through the use of human effort. In addition, the robot can be used in places where the use of human labor in such places is undesirable for moving components and for careful access to the environment.

  [0004] This is particularly important in semiconductor processing systems where substrate misplacement or misalignment results in costly damage and / or unscheduled system maintenance. Misaligned substrates are often damaged, can damage other substrates and equipment, or can be discarded due to misalignment and discarded. For example, a substrate installed on an end effector of a robot in a semiconductor processing system may come into contact with a substrate that is displaced when the substrate fixed to the robot moves. When the substrates contact each other, one of the substrates can be damaged. Further, if one or both of the substrates are removed, the system must shut down for substrate removal before further processing occurs. Searching for removed substrates requires access to internal parts of the system operation under vacuum, and several hours of production time will be spent decontaminating and re-establishing the vacuum environment in the damage chamber .

  [0005] To ensure accurate positioning of the substrate on which the robot has moved, the reference point or coordinates of the desired or predetermined position of the robot's end effector are typically entered into the robot controller's memory as part of the calibration procedure. Yes. Obtaining the reference coordinates generally involves jogging the end effector in place, usually by manual or automated sequences. The arrival of the robot's end effector in place can be confirmed by manually observing the position of the end effector or by causing a sensor such as a limit switch to trigger the end effector (or other component of the robot). it can. This sequence is typically repeated until all reference coordinates for each critical position within the robot's range of motion throughout the system are established (ie, entered into the robot or robot controller's memory). Once the reference coordinates are established, the robot can accurately and accurately move the end effector to the critical position by referring to the reference coordinates.

  [0006] In many semiconductor processing systems, robot end effector jogging and confirmation of end effector arrival at reference coordinates is done manually. An operator must visually estimate the position of the end effector by observing the location of the end effector relative to the object or target in the processing system. In order to properly view the end effector when performing this task, the processing system is normally open to the surrounding environment. Although not desirable, this places the operator at a location that is exposed to the robot's range of motion where human and system damage can occur. Therefore, to prevent possible damage to the operator, the processing system shuts down normally and the robot inadvertently contacts the operator so as not to damage the product, tool or operator. Since the system is exposed to the surrounding environment, the decontamination procedure must be performed before processing. In addition, prolonged pump down must be performed to bring the system back to operating pressure. During the time the system is shut down, no wafers are processed and valuable production time is lost. This all results in an undesirable loss of production capacity, and thus a further loss of capacity whenever recalibration is required.

  [0007] Accordingly, there is a need for an improved calibration and method for determining the position of an object.

Summary of the Invention

  [0008] One aspect of the present invention generally provides a vision system and method for calibrating the motion of a robot installed in a processing system. In one embodiment, a vision system for a processing system includes a camera positioned on the processing system and a calibration wafer. The camera is positioned on the robot and is adapted to obtain image data of a calibration wafer installed at a predetermined location in the processing system. The robot motion is calibrated using image data.

Detailed description

  [0009] A more specific description of the invention, briefly summarized, will be made with reference to the embodiments illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings show only typical embodiments of the invention and are therefore not to be considered as limiting its scope, and therefore the invention is not limited to other equally effective implementations. The form can be tolerated.

  [0024] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to all figures.

  [0025] The present invention generally provides a vision system for capturing images within a semiconductor processing system and associated equipment. Images can be used to calibrate the position of the robot's end effector and for system inspection. The present invention is illustratively described below with reference to determining the position of the end effector of a robot within a semiconductor processing system or cluster tool. However, it should be understood that the present invention can be used to perform various inspection and / or calibration functions within a semiconductor processing system without having to open the system to the ambient (ie, ambient) environment. is there. Furthermore, the present invention has utility in other semiconductor processing system configurations such as chemical mechanical polishing systems and electrochemical deposition / polishing systems, where images acquired from a mobile camera are desirable.

  FIG. 1 depicts one embodiment of an exemplary processing system 190 that includes a vision system 150 that can be used to capture images in the processing system 190. The vision system 150 generally includes a camera assembly 100 and a controller 140 for processing and / or displaying images viewed by the camera assembly 100. Camera assembly 100 is adapted to be transferred to system 190 by one or more substrate transfer robots of system 190. Thus, the image provided by the camera assembly 100 to the controller 140 can be used to determine the position of the robot for calibration purposes and / or visual chamber inspection without having to expose the interior of the system 190 to the surrounding environment. The images obtained by the camera assembly 100 can also be used for other purposes.

  [0027] The exemplary processing system 190 depicted in FIG. 1 generally includes a central transfer chamber 194 having a plurality of processing chambers 192 coupled thereto. The processing chamber 192 may be any type of processing chamber associated with semiconductor processing, including, among others, a chemical vapor deposition chamber, an atomic layer deposition chamber, a physical vapor deposition chamber, a direction chamber, a degas chamber, Including but not limited to a pre-clean chamber, an etching chamber and a heat treatment chamber. An example of such a processing chamber is available from Applied Materials, Inc., located in Santa Clara, Calif., And is also available from Applied Materials, such as PRODUCER® (Trademark), ENDURA (R) and CENTURA (R) species are available with transfer chambers.

  [0028] A port 188 is defined between each processing chamber 192 and transfer chamber 194 to allow entry and exit of the substrate (and camera assembly 100) from the processing chamber 192. Port 188 is selectively sealed by a slit valve (omitted from FIG. 1 for clarity). A transfer robot 196 having an end effector 198 is centrally located in the transfer chamber 104 to facilitate transfer of the substrate (and camera assembly 100) to the surrounding processing chamber 192. An example of a transfer robot that can be used is also available from Applied Materials, Inc. VHP (R) robot available from Other robots can also be used.

  [0029] One or more load lock chambers 184 are coupled between the transfer chamber 104 and the factory interface 180. Two load lock chambers 184 are shown in the embodiment depicted in FIG. The load lock chamber 184 facilitates substrate transfer between the vacuum environment of the transfer chamber 194 and the substantially outside air environment of the factory interface 180. An example of a load lock chamber that can be used is described in US Pat. No. 6,270,582, issued Aug. 7, 2001 to Rivkin et al., Which is hereby incorporated by reference in its entirety.

  [0030] The factory interface 180 has an interface robot 182 and includes a plurality of bays 178 adapted to receive a substrate storage cassette 174. Each cassette 174 is configured to store a plurality of substrates 174. The factory interface 180 is generally maintained at or near atmospheric pressure. In one embodiment, filtered air is provided to the factory interface 180 to minimize particle concentration in the factory interface and thus substrate cleanliness. An example of a factory interface that can be adapted to enjoy the benefits of the present invention is described in US patent application Ser. No. 09 / 161,970 filed Sep. 28, 1998 by Kroeker, see in its entirety. As incorporated herein.

  [0031] The interface robot 182 is generally similar to the transfer robot 196 described above. The interface robot 182 includes an end effector similar to the end effector 198 of the transfer robot 196 and is therefore referenced with the same reference number. Interface robot 182 is adapted to transfer substrates between cassette 176 and load lock chamber 184.

  [0032] A docking station 172 is installed in the factory interface 180. The docking station 172 provides a storage area for the camera assembly 100 in the system 190 so that the camera assembly 100 can be calibrated, recalibrated, or not required to be introduced into the system 190 via a cassette 174 or other access port. The inspection procedure becomes easy. Alternatively, docking station 172 may be installed elsewhere in system 190. In another embodiment, the camera assembly 100 can be stored in the cassette 174 to allow introduction and removal from the system 190. Alternatively, the camera assembly 100 can be removed from the system 190 when not in use. One embodiment of the docking station 172 is further described below with reference to FIGS.

  [0033] Because the camera assembly 100 is adapted to be transported by the robots 196 and 182, calibration of the position of the end effector 198 can be obtained at any position within the processing system 190. For example, the camera assembly 100 is used to calibrate the position of the transfer robot in any one of the processing chamber 192, transfer chamber 194 or load lock chamber 184 to ensure that the substrate is placed accurately and repeatably. can do. The camera assembly 100 can be used to calibrate the position of the end effector 198 of the factory interface robot 182 in any one of the substrate storage cassette 176, the load lock chamber 184, or the docking station 172. Precise positioning of the substrate increases process repeatability while reducing damage to the substrate and equipment due to substrate misalignment. In addition, the mobility of the camera assembly 100 allows calibration and visual inspection of the interior of the processing system 190 without the risk of loss of transfer and human vacuum in the processing chambers 194 and 192. Furthermore, productivity is increased because processing can continue while inspection / calibration is performed.

  [0034] The camera assembly 100 generally includes a camera 104 mounted on a placement plate 106, a power source 138, and a transmitter 156. The camera assembly 100 should have a height that can be transferred through the various slit valves and ports in the system 190, and the end effector 198 of the robot 196 is overloaded when placed thereon. It should have the same weight as the substrate so that it does not sag.

  [0035] Placement plate 106 is typically composed of aluminum, stainless steel, plastic or other rigid material. In embodiments where the camera assembly 100 is exposed to high temperatures, for example in a processing chamber 192 that performs chemical vapor deposition at a temperature of about 350 degrees Celsius or higher, the placement plate 106 is preferably non-conductive with a low coefficient of thermal expansion. Consists of materials. Placement plate 106 is generally configured to support camera 104 on end effector 198 of transfer robot 196.

  [0036] The placement plate 106 may be any shape or geometry sufficient to support the camera 104 on the end effector 198 without being removed from the robot during transfer. In one embodiment, at least a portion of the periphery of the placement plate 106 has a radius configured to fold back a conventional substrate (i.e., substantially the same). For example, the placement plate 106 can include at least a portion of the periphery having a radius of about 150 mm, about 100 mm, or about 50 mm to fold a 300 mm, 200 mm, or 100 mm size substrate. Alternative configurations of the placement plate 106 can fold other standard, conventional or custom sized substrates, including polygonal flat panels.

  [0037] The camera 104 is adapted to capture images within the processing system 190. The camera 104 provides signals and video images. In one embodiment, the camera is a monochrome board mounted camera available from Edmund Industrial Optics, Barrington, New Jersey.

  [0038] The power source 138 typically provides power to the camera 104 and the transmitter 156. The power source 138 may be remote such as facility power, or may be built into the camera assembly 100 like a battery.

  [0039] In one embodiment, the power source 138 is a battery suitable for use in a vacuum environment. Preferably, the power source 138 is suitable for intermittent use at temperatures above about 200 degrees Celsius. One power supply 138 is a battery model number 3S1P available from SouthWest Electronics Energy Corporation.

  [0040] The transmitter 156 generates a signal representing an image viewed by the camera 104. The transmitter 156 can provide signals to the controller through control wires via robots and broadcast signals (ie, wireless signals). One transmitter that can be used is MVT-10 available from Supercircuits.

  [0041] The controller 140 is adapted to receive an image viewed by the camera 104 from the transmitter 156. The controller 140 includes a central processing unit (CPU) 144, a support circuit 146, and a memory 142. The CPU 144 may be one of any form of computer processor that can be used in an industrial setting to control the various chambers and sub-processors. Memory 142 is coupled to CPU 144. The memory 142 or computer readable medium is one or more readily available memories such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or other form of digital storage. It may be local or remote. Support circuit 146 is coupled to CPU 144 and supports the processor in a conventional manner. These circuits include caches, power supplies, clock circuits, input / output circuits, subsystems, and the like.

  [0042] Receiver 154 is coupled to controller 140 to facilitate transfer of signals generated by transmitter 156 to controller 140. One receiver that can be used is the MVR-10 available from Supercircuits. In some cases, monitor 148 may be coupled to controller 140 for viewing images from camera 104.

  [0043] FIG. 2A depicts a top view of the camera assembly 100 supported by an end effector 198 located under the placement plate 106. FIG. As depicted in FIG. 2A, the placement plate 106 includes respective holes 204 formed in the robot end effector 198 to increase the positional accuracy between the placement plate 106 and the robot end effector 198. One or more placement pins 202 are included for interfacing. The pins 202 extend from the first side 206 of the deployment plate 106 facing the end effector 198, while the opposing second side 208 of the plate 106 supports the transmitter 156.

  [0044] The placement plate 106 further includes an opening 210 that is positioned in alignment with a corresponding opening 222 formed through the end effector 198. The opening 210 may be a hole formed in the plate 106 that facilitates viewing an object on the first side 206 of the plate 106 facing the camera 104, or a transparent portion of the plate 106. In the embodiment depicted in FIG. 2A, the aperture 210 allows the lens 216 of the camera 104 to extend through the placement plate 106 to a position below the first side 206. The lens 216 is selected to have a depth of field 218 such that the object seen by the camera 104 is in focus. In one embodiment, lens 216 is a 4.7 mm focal length lens, also available from Edmund Industrial Optics.

  [0045] In another embodiment of the camera assembly 100 depicted in FIG. 2B, the opening 210 is filled with a window 212 of transparent material such as acrylic, quartz or polycarbonate. Alternatively, the entire arrangement plate 106 may be made of a transparent material.

  The camera 104 is positioned on the second side 208 of the placement plate 106 to position the lens 216 over the window 212. In this position, the camera 104 can see objects such as the substrate support 186 seen in FIG. 1 through the aperture 210 / window 212 to obtain an image representing the position of the end effector 198 in the system 190. In some cases, the camera 104 is mounted on a placement plate 106 facing in the opposite direction so that an image on the second side 208 of the placement plate 106 can be viewed, thereby varying the upper region of the processing system 190. Can be inspected without removing the chamber lid.

  [0047] The window 212 may optionally include a landmark 214. The landmark 214 provides a reference or “crosshair” for the image from the camera 104 through the opening 210 and the window 212. The indicia 214 may be a circle, a cross, or other mark suitable for delineating a reference point. The landmark 214 can be utilized to provide a basis for comparing images. In embodiments where landmark 214 is utilized at the aperture, lens 216 should be selected to provide a depth of field 218 that includes landmark 214.

  [0048] Referring again to FIG. 2A, a light 220 powered by a power source 138 can be coupled to the placement plate 106 to illuminate an object under the first side 206 of the plate 106. FIG. The light 220 is normally positioned on the side of the aperture 210 so that the beam generated by the light 220 can illuminate the object or surface under the aperture 210. In one embodiment, light 220 is a light emitting diode that extends through hole 224 in placement plate 106 (as seen in the top view of one embodiment of end effector 198 depicted in FIG. 2C). The light 220 extends below the end effector 198 and can be configured to pass outside the end effector 198 or through a hole 226 formed in the end effector 198.

  [0049] A switch 240 is coupled to the placement plate 106 so that the camera assembly 100 can be activated. The switch 240 may be a manual on / off switch, or may be automatically switched on by a controller or other means. In one embodiment, the switch 240 is a proximity that detects the presence of the end effector 198 relative to or near the first side 206 of the placement plate 106 when the end effector 198 is installed under the camera assembly 100. Sensor, optical sensor, limit switch or other sensor / switch. This allows switch 240 to activate light 220, camera 104, and transmitter 156 when camera assembly 100 is supported by robot end effector 198, thereby conserving battery power. .

  [0050] FIGS. 3A-3B depict one embodiment of a docking station 172 adapted to extend the battery life of the power source 138. FIG. Docking station 172 generally includes cradle 302 and charging mechanism 320 while being adapted to support camera assembly 1000 when not in use. The cradle 302 is configured to support the camera assembly 100 thereon. Because the geometry of the cradle 302 is highly dependent on the configuration selected for the placement plate 106, the cradle 302 can be configured with numerous variations that hold the camera assembly 100 securely, while the end effector of the interface robot 182. 198 places the camera assembly 100 so that it can be retrieved therefrom.

  [0051] In one embodiment, the cradle 302 is made of a rigid material such as aluminum, stainless steel, or a polymer, and includes a mounting portion 304 and a support portion 306 that extends from the mounting portion 304. Yes. The mounting portion 304 is coupled to the factory interface 180 by a plurality of fasteners 308.

  [0052] The support portion 306 includes a first arm 310 and a second arm 312 that extend from the mounting portion 304 to support a camera assembly 100 that is not in use. The arms 310 and 312 are spaced to allow the end effector 198 of the robot 182 to pass there between, so that the end effector 198 places the camera assembly 100 without contacting the cradle 302 and supports portions. This can be retrieved from 306 arms 310 and 312.

  [0053] Each arm 310, 312 includes a pair of support posts 314. Each support post 314 includes a seat 316 for supporting the camera assembly 100 and a lip 318 for stopping the camera assembly 100 to hold the camera assembly 100 on the seat 316.

  [0054] Optionally, the cradle 302 may include a charging mechanism 320. The charging mechanism 320 is adapted to recharge the power source 138 of the camera assembly 100 while being stored on the cradle 302 when not in use. In one embodiment, the charging mechanism 320 includes a pair of contact pins 322 that are coupled to a charger 324 located outside the system 190. Contact pin 322 is coupled by an actuator 326 to a tab 328 extending from mounting portion 304.

  [0055] A sensor 330, such as a proximity sensor or a limit sensor, is coupled to the cradle 302 that detects the presence of the camera assembly 100. When the camera assembly 100 is detected, the actuator 326 moves the contact pins 322 that are in contact with a pair of conductive contact pads 322 installed on the camera assembly 100. Since contact pad 322 is coupled to each pole of power source 138, power source 138 is electrically coupled to charger 324 via contact pin 322 to recharge power source 138 when not in use. When the power supply 138 is fully charged, that is, when the controller 140 commands the robot 182 to search for the camera assembly 100, the actuator 326 lifts the pin 322 without the camera assembly 100 so that the robot 182 contacts the pin 322. Without having to lift the camera assembly 100 from the docking station 172.

  [0056] Since the controller 140 can be configured to monitor the charging of the power source 138, the charging is terminated when the power source 138 returns to a predetermined charge level. Alternatively, other means such as a dedicated logic circuit (not shown) locally mounted on the docking station 172 are utilized to control and / or monitor charging as the operation of the contact pin 211 is controlled. can do.

  [0057] Returning to FIG. 1, the controller 140 receives image information viewed by the camera 104. The image information can be processed by the controller 140 to determine the position of the end effector and / or view portions of the processing system. In the embodiment depicted in FIG. 1, the controller 140 displays an image 152, for example, an image of a substrate support 186 installed in one of the processing chambers 192, on the monitor 148 so that the operator can easily view the image 152. Like that.

  [0058] In one mode of operation, the image 152 displayed on the monitor 148 is used to manually jog the robot 196 to a predetermined position or target on a vacuum port formed in the substrate support 186, for example. An end effector 198 can be placed and this image is displayed on the monitor 148 as a port image 170. To facilitate the distance required to move the end effector 198, the display 150 causes the grid 158 to project optically. In the grid 158, the distance between the target image, for example, the port image 170 and the landmark image 160, is eliminated by counting the number of grid lines between the port image 170 and the landmark image 160 along each axis. It is configured as follows.

  [0059] FIG. 4 is a flow chart depicting one embodiment of a calibration procedure 400 that can be used to find the reference coordinates of a robot that places an end effector in a determined position. Such locations include, but are not limited to, any location where a substrate is placed or retrieved by the robot of system 190. Although the procedure 400 is described as aligning the end effector 198 of the transfer robot 198 with the substrate support 186 of one of the processing chambers 194, the procedure 400 may be performed elsewhere within the range of motion of any system robot. This can be used to calibrate the position of the robot at that location. In step 402, the camera assembly 100 is positioned on the end effector 198 of the transfer robot 196. This step includes transferring the camera assembly 100 from a location remote from the robot 196. In step 404, the robot 196 is jogged to a position within the processing chamber 192 in the X / Z plane so that the image 152 of the substrate support 186 is displayed on the monitor 148. In step 406, the robot 196 is manually jogged in the X / Z plane to align the landmark 214 with the image 152, ie, a predetermined portion of the target, eg, the port image 170. In step 408, the aligned position of the end effector 198 is recorded as a reference coordinate in the X / Z plane.

  [0060] Once the port image 170 and the landmark are aligned, the elevation angle of the end effector 198 is moved to a predetermined position by jogging the end effector 198 of the robot 196 along the y-axis at step 410. Arrival at a predetermined location can be determined by comparing the relative sizes of the landmark 152 and the port image 170 at step 412. This comparison is facilitated by utilizing landmarks 212 that match the size and / or geometry of the target (ie, port image 170) when end effector 198 of robot 196 is at the proper elevation. In step 414, the elevation angle of the end effector 198 is recorded as a reference coordinate along the y-axis.

  [0061] FIG. 5 is a flow chart depicting another embodiment of a calibration procedure 500 that can be used to find a robot reference coordinate that places an end effector in a predetermined position. Although the procedure 500 is described as aligning the end effector 198 of the transfer robot 198 with the substrate support 186 of one of the processing chambers 194, the procedure 500 can be performed elsewhere within the range of motion of any system robot. This can be used to calibrate the location of the robot at that location. In step 502, the camera assembly 100 is positioned on the end effector 198 of the transfer robot 196. In step 504, controller 140 directs robot 196 to a position within processing chamber 192 so that image 152 of substrate support 186 is viewed by camera 104. In step 506, the controller 140 compares the image 104 viewed by the camera 104 with a reference image stored in the memory 142 of the controller 140. In step 508, the controller 140 eliminates the distance between the current position of the robot 196 and the determined position of the X / Z plane and moves the end effector 198 accordingly. Steps 506 and 508 are repeated until the end effector 198 of the robot 196 reaches the determined position where the X / Z reference coordinates of the end effector 198 are recorded by the controller 140 at step 510.

  [0062] Once the X / Z reference coordinates of the end effector 198 are obtained, the elevation angle of the end effector 198 is moved to a predetermined position by moving the end effector 198 of the robot 196 along the y-axis in step 512. It is done. Arrival at a predetermined location can be determined at step 514 by comparing the relative size of the image viewed by the camera 104 with reference information. For example, the elevation angle of the camera 104 can be adjusted until the number of pixels in the target image reaches a predetermined number. In one alternative, the relative size of the target image may be compared to the landmark 212 as seen by the camera 104. When the end effector 198 of the robot 196 reaches the determined Y axis position, the Y reference coordinates of the end effector 198 are recorded by the controller 140 at step 516. The X, Y and Z reference coordinates may be simultaneous but are intended to be obtained in any order.

  [0063] FIG. 6 depicts another method 600 in which the present invention may be utilized. In step 602, the camera assembly 100 is positioned on the end effector of the transfer robot 196 (or other robot in the system 190). In step 604, the controller 140 commands the robot 196 to move the camera assembly 100 to a predetermined position and / or along a predetermined route through the system 190. In step 606, the image is sent to the controller 140. In step 608, the transmitted image is interpreted by the controller 140. For example, the image may be displayed on monitor 148 for visual inspection inside system 190. Alternatively, the image may be compared with a reference image stored in the memory 142 of the controller 140. The images may also be used for other purposes such as sales and technical demonstrations.

  FIG. 7 depicts another embodiment of a vision system 700 that can be used to obtain an image of the processing system 750. The processing system 700 is substantially similar to the processing system 190 described with reference to FIG. 1, and is therefore a single unit coupled to a transfer chamber 754 having a transfer robot 756 installed therein. Only the processing chamber 752 is shown in a concise manner.

  [0065] The vision system 700 generally includes a controller 702, a camera 704, and a reflector 706. The reflector 706 is typically coupled to the end effector 758 in a direction in which images outside the camera's field of view are viewed by the camera 704. The reflector 706 may be fixed, glued or otherwise attached to the end effector 758. Alternatively, the reflector 706 may be coupled to a placement plate 710 configured similar to the placement plate 106 described above, so that the reflector 706 (and the placement plate) may be removed from the end effector when not in use. Good.

  [0066] In the embodiment depicted in FIG. 7, the reflector 706 is coupled to the bottom side 720 of the end effector 758 and includes a reflective surface 708. The reflective surface 708 is typically fabricated from polished stainless steel or other material that provides optical quality reflection. The reflective surface 708 is oriented at approximately 45 degrees with respect to the field of view of the camera 704. Thus, images of objects under the end effector 758 and outside the camera's field of view can be captured by the camera 704 positioned away from the processing chamber 752. The captured image can be used for the inspection and calibration described above.

  [0067] The reflector 706 can be configured to allow the camera 704 to view an object at a determined location in the system 750 by changing the angular orientation of the reflective surface 708. The reflector 760 can be configured to provide an image above, below or along the end effector 758. Alternatively, the reflector 706 may be a prism, lens, or other optical device adapted to provide an image outside the field of view of the camera.

  [0068] The reflector 706 may also be coupled to the placement plate in such a way that the reflector 706 is moved relative to the end effector 758 so that multiple objects are viewed by the camera 704 with a fixed line of sight. A reflector having controllable positioning will be described below with reference to FIG.

  [0069] Controller 702 and camera 704 are generally similar to controller 140 and camera 104 described above. The camera 704 is typically mounted on a portion of the transfer robot 756 that remains outside the process chamber 752 (eg, remains in the transfer chamber 754) when the end effector 758 of the robot 756 is inserted into the process chamber 752. Yes. By mounting the camera 704 in a position that does not enter the processing chamber 752, the vision system 700 can be easily used in a hotter environment that can damage the camera. Thus, the image is obtained in a hot processing chamber without waiting for cooling.

  [0070] In an embodiment of the vision system 700 coupled to a factory interface robot, eg, the robot 182 depicted in FIG. 1, the environment accessed by the interface robot is typically exposed to the end effector of the transfer robot. To be more comfortable than the environment in which it is, the camera 704 can be coupled to any part of the interface robot that maintains the reflector 706 within the camera's field of view.

  [0071] In one embodiment, camera 704 is coupled to a list 760 that couples end effector 758 to link 762 of transfer robot 756. Alternatively, camera 704 may be coupled to link 762 or statically positioned within transfer chamber 760. When camera 704 is coupled to system 750 via transfer robot 756, local power supply 712 and transmitter 714 are not required because camera 704 may be incorporated into controller 702 via robot 756 and transfer chamber 754. Absent. Alternatively, a power source and transmitter similar to the power source 138 and transmitter 156 described above can be coupled to the camera 704 on the robot 756 or near the system 750.

  [0072] FIG. 8 is a plan view of another embodiment of a camera assembly 800. FIG. Camera assembly 800 is similar to camera assembly 100 described above, except that camera 104 of camera assembly 800 is movably mounted on camera assembly 800. The camera 104 can view the object without moving the robot or end effector (not shown) by changing the line of sight of the camera 104 relative to the placement plate 106 that supports the camera 104. . Movement of camera 104 relative to placement plate 104 is facilitated by gimbal assembly 802. The gimbal assembly 802 may be any device that can change the orientation of the camera 104, eg, a ball joint, universal joint, or other mechanism that can change the view of the camera 104 through at least one plane. .

  [0073] In the embodiment depicted in FIG. 8, the gimbal assembly 802 includes a turntable assembly 804 to which a pivot assembly 806 is coupled. The pivot assembly 806 carries the camera 104 and is adapted to rotate the camera 104 relative to an axis 808 that is installed parallel to the placement plate 106. The turntable assembly 804 is adapted to rotate about an axis 810 that is perpendicular to the axis 808 and concentric with the opening 210 that is located through the placement plate 106. The turntable assembly 804 is adapted to rotate the camera 104 about the axis 810.

  [0074] With further reference to the cross-sectional view of FIG. 9, the turntable assembly 804 includes a race 814 that holds a turntable 816. The turntable 816 has a toothed periphery 818 that meshes with the drive motor 820. Drive motor 820 is coupled to controller 140 that instructs drive motor 820 to control the direction of rotation of turntable 816.

  [0075] The turntable 816 includes a tab 822 that is coupled proximate to the periphery 818. Tab 822 has a hole 824 and is formed, at least in part, through a hole adapted to interface with piston 828 of actuator 826 that is coupled to placement plate 106. When the turntable 816 is in a predetermined angular direction, the position of the turntable 816 can be locked or fixed around the shaft 810 by operating the piston 828 to engage the hole 824.

  [0076] The pivot assembly 806 has a pair of brackets 830 that span an opening 838 formed in the center of the turntable 816 that is aligned with the opening 210 of the placement plate 106. The camera 104 is supported so as to be rotatable between the brackets 830 by a shaft 832 installed along an axis 808. One end of the shaft 832 includes a gear 834 that interfaces with a drive motor 836 that is coupled to the turntable 816. Drive motor 836 is coupled to controller 140 that commands motor 836 to control the direction of rotation of camera 104 relative to bracket 830 about axis 808. Thus, the turntable assembly 804 and the pivot assembly 804 can direct the camera 104 to have an upper hemisphere field (UVOF) and a lower hemisphere field (LFOV) from which images can be obtained.

  [0077] With further reference to FIG. 10, the gear 834 includes at least a first placement hole 1002 formed at least partially therethrough. The hole 1002 is adapted to interface with the piston 1004 of the actuator 1006 that is coupled to the turntable 816. When the gear 834 is in a predetermined angular direction, for example, when the camera 104 is capturing along (eg, facing) the axis 810 via the opening 210 in the placement plate 106, the piston 1004 is actuated to activate the hole. By engaging 1002, the direction of the camera 104 can be locked or fixed about the axis 808. Hole 1008 can be provided to bracket 830 to receive piston 1004 after holding gear 834 more securely through hole 1002 of gear 834. Alternatively (in addition), the second hole 1010 may be formed at least partially via the gear 834 at a location rotated 180 degrees about the axis 808 with respect to the first hole 1002 to the upper viewing position. The camera 104 can be oriented.

  [0078] In one embodiment, the gimbal assembly 802 is lockable to actuate the pistons 828 and 1004 to hold the camera 104 in a direction visible along the axis 810 through the opening 210. In this lock condition, the position calibration of the robot can be accurately obtained by the above method. Furthermore, in the unlocked position, the camera 104 can be swiveled in various directions, whether the robot is moving or not, so that it can be seen substantially from the whole system. Is advantageously available for system inspection without interruption of the normal processing path and without loss of vacuum in the area of the system under inspection.

  [0079] FIG. 11 depicts a reflector assembly 1100 that can be used in place of the reflector 704 of the vision system 700 described above with reference to FIG. The reflector assembly 1100 is generally similar to the camera assembly 800 except that the gimbal assembly 802 of the reflector assembly 1100 controls the orientation of the reflector 1102. Accordingly, the camera 704 (shown in FIG. 7) moves a robot or end effector (not shown) by changing the angle / direction of the reflector 1102 relative to the camera 104 as depicted by arrow 1106. The image of the object reflected by the reflector 1102 outside the camera's line of sight can be seen.

  [0080] In the embodiment depicted in FIG. 11, the gimbal assembly 802 is mounted on the placement plate 106 and includes a turntable assembly 804 to which a pivot assembly 806 is coupled. The pivot assembly 806 has a reflector 1102 mounted thereon and is adapted to rotate the reflector 1102 relative to an axis 808 that is installed parallel to the placement plate 106. The turntable assembly 804 is adapted to rotate about an axis 810 that is perpendicular to the axis 808. The turntable assembly 804 is adapted to rotate the reflector 1102 about the axis 810. The combination of movement between the turntable assembly 804 and the pivot assembly 806 directs the reflective surface 1104 of the reflector 1102 so that the camera 704 is positioned when the orientation of the reflector 1102 is positioned as commanded by the controller 140. Images of objects above, below and along the plate 106 can be captured.

  [0081] FIG. 12 is provided on the substrate support 186 that is used to obtain correction data and is not limited to the above method, but is used to improve the accuracy of the primary position data obtained using this. FIG. 2 is a partial cross-sectional view of a processing system 190 having a calibration wafer 1200 that is in contact. After calibration data regarding the position of the end effector 198 relative to another object, such as the substrate support 186, is obtained, the calibration wafer 1200 is retrieved by the end effector 198 of the robot 196. In the embodiment depicted in FIG. 12, a camera assembly 100, or similar device for obtaining image data, is utilized for collecting position data. The position of the camera assembly 100 from which the primary data was obtained is referred to as P1. Calibration wafer 1200 may be stored locally in the processing system in one of the substrate storage cassettes, or may be introduced into the processing system as needed.

  [0082] Calibration wafer 1200 is typically the size and shape of a conventional wafer and can be fabricated from quartz, silicon, stainless steel or other suitable material. The calibration wafer 1200 may be transparent so that a substrate support 186 or other object positioned under the calibration wafer 1200 is visible through the calibration wafer 1200. Alternatively, the calibration wafer 1200 may be translucent or non-transparent.

  [0083] The calibration wafer 1200 includes indicia 1202 for identifying a reference point on the calibration wafer 1200, typically the center of the wafer. The indicia 1202 can be marked, printed, embossed, embossed or otherwise marked on the surface of the calibration wafer 1200. It is contemplated that the landmark may also be a physical attribute of the calibration wafer 1200, such as a notch, flat, hole, slot, perimeter or other geometric or visual feature. Thus, ordinary production wafers can also be used. In the embodiment depicted in FIG. 12, the calibration wafer 1200 includes a landmark 1202 printed in the center of the top surface 1204 of the calibration wafer 1200.

  [0084] After the calibration wafer 1200 is positioned on the substrate support 186, the camera assembly 100 is retrieved by the robot 196 and transferred to a position P1 on the substrate support 186 on which the calibration wafer 1200 is mounted. The camera assembly 100 captures and transmits data provided to the controller 140 to determine the correction of the reference data being utilized to place the substrate at a predetermined position on the substrate support 186.

  [0085] In one mode of operation, the captured data includes an image of the substrate support 186 and the calibration wafer 1200 displayed on the monitor 148 as a substrate support image 152 and a calibration wafer image 1204. The operator can see an offset between an image 1206 of the landmark 1202 and a reference object such as a port image 170 of a port (not shown) in the center of the top surface of the substrate support 186 that is visible through the calibration wafer 1200. From the offset, the operator can determine the positional correction of the primary data necessary to center the calibration wafer 1200 (ie production wafer) in the center of the substrate support 186. Alternatively, as described above, the controller 140 compares the image of the substrate support 186 and the calibration wafer 1200 and is required to accurately place the calibration wafer 1200 or production wafer at a predetermined (ie, center) position on the substrate support 186. A correction required for positioning the end effector is determined. The positional correction obtained while using the calibration wafer 1200 can be used to correct robot motion as part of an initial system calibration routine or as part of a recalibration routine performed over time. it can.

  [0086] In another mode of operation, the captured data is primarily an image 1206 of a landmark 1202. Because the location of the image 1206 of the landmark 1202 can be visually or digitally compared to stored reference data, such as the port image 170 stored in memory, the correction for placing the substrate is the end effector 198. And a further substrate handoff between the substrate support 186 is determined.

  [0087] Accordingly, a vision system is provided that facilitates capturing images within a semiconductor processing system. With the vision system, calibration and inspection procedures are performed with minimal operator interaction and without exposure to the atmospheric environment inside the system. Furthermore, the vision system is provided for in-situ inspection and calibration at or near operating temperature and provides more accurate position data of the robot position obtained without interruption of substrate processing. .

  [0088] Although various embodiments incorporating the teachings of the present invention have been shown and described in detail herein, those skilled in the art will readily appreciate numerous other various embodiments that still include these teachings. Can be devised.

A simplified plan view of the cluster tool and vision system is depicted. 1 is a front view of one embodiment of a camera assembly installed on an end effector of a robot. FIG. FIG. 6 is a front view of an alternative embodiment of a camera assembly installed on a robot end effector. It is a top view of one embodiment of an end effector. FIG. 6 is a top view of one embodiment of a docking station. 2 is a cross-sectional view of one embodiment of a docking station. FIG. 2 depicts a flowchart of one operating mode of the vision system of FIG. 3 depicts a flowchart of another mode of operation of the vision system of FIG. FIG. 1 depicts a flowchart of another mode of operation of the vision system. Figure 3 depicts another embodiment of a vision system. 2 is a plan view of one embodiment of a camera assembly having a gimbal system. FIG. FIG. 9 is a cross-sectional view of the gimbal system taken along section line 9-9 of FIG. FIG. 10 is a cross-sectional view of the gimbal system taken along section line 10-10 of FIG. FIG. 6 is a cross-sectional view of another embodiment of a camera assembly. FIG. 2 is a partial cross-sectional view of the processing system of FIG. 1 illustrating another mode of operation of the vision system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Camera assembly, 104 ... Camera, 106 ... Arrangement plate, 138 ... Power supply, 140 ... Controller, 142 ... Memory, 144 ... CPU, 148 ... Monitor, 150 ... Vision system, 154 ... Receiver, 156 ... Transmitter, 174 ... cassette, 180 ... factory interface, 182 ... interface robot, 186 ... substrate support, 190 ... processing system, 192 ... processing chamber, 194 ... transfer chamber, 196 ... transfer robot, 198 ... end effector, 202 ... placement pin, 206 ... 1st side, 208 ... 2nd side, 210 ... opening, 212 ... window, 214 ... landmark, 216 ... lens, 220 ... light, 222 ... opening, 240 ... switch, 302 ... cradle, 304 ... mounting part 306 ... Support part 310 ... No. Arm, 312 ... second arm, 316 ... seat, 318 ... lip, 324 ... charger, 326 ... actuator, 328 ... tab, 700 ... vision system, 702 ... controller, 704 ... camera, 706 ... reflector, 708 ... Reflective surface, 710 ... Placement plate, 750 ... Processing system, 752 ... Processing chamber, 754 ... Transfer chamber, 756 ... Transfer robot, 800 ... Camera assembly, 802 ... Gimbal assembly, 804 ... Turntable assembly, 806 ... Pivot assembly, 808 ... shaft, 810 ... shaft, 820 ... motor drive, 822 ... tab, 830 ... bracket, 834 ... gear, 836 ... drive motor, 1002 ... hole, 1004 ... piston, 1006 ... actuator, 1102 ... reflector, 1104 ... anti Surface, 1200 ... calibration wafer, 1202 ... mark.

Claims (36)

At least one robot adapted for use in a semiconductor processing system;
Calibration wafers supported by the processing system;
An end effector coupled to the robot;
A camera selectively positioned by the robot;
A transmitter coupled to the camera;
A vision system for a semiconductor processing system, comprising: a receiver for receiving an image of the calibration wafer transmitted by the camera.   The system of claim 1, wherein the robot is housed in a vacuum chamber.   The system of claim 1, further comprising a plate coupling the camera. The plate further comprises:
An opening formed through it,
The camera adapted to obtain an image through the aperture;
The system of claim 3, comprising: The end effector of the robot further comprises:
The system of claim 3, comprising a hole formed through the end effector adapted to allow the camera to be viewed therethrough. The plate further comprises:
The system of claim 4, comprising at least one locating pin extending from and received by a hole formed in the end effector.   The system of claim 1, wherein the calibration wafer is transparent.   The system of claim 1, wherein the calibration wafer further comprises a landmark for determining a position of the calibration wafer.   9. The system of claim 8, wherein the landmark is described, printed, embossed, embossed or marked on at least one surface of the calibration wafer.   The system of claim 8, wherein the landmark is a physical attribute.   The system of claim 10, wherein the physical attribute of the landmark is at least one of geometric or visual features.   The system of claim 10, wherein the physical feature of the landmark is at least one of a notch, a flat, a hole, a slot, and a perimeter of the calibration wafer. A method for calibrating the motion of a robot installed in a semiconductor processing system, comprising:
Positioning a calibration wafer in a semiconductor processing system;
Positioning the camera on the robot;
Viewing the calibration wafer with the camera;
Determining a relative distance between an image of the calibration wafer and a determined position;
A method comprising: The step of determining further comprises:
The method of claim 13, comprising comparing the image of the calibration wafer with a landmark displayed on a monitor. The step of determining further comprises:
The method of claim 13, comprising comparing the image of the calibration wafer with a reference image stored in the controller. A method for calibrating the motion of a robot installed in a semiconductor processing system, comprising:
Moving a calibration wafer supported by a robot to a reference position in a semiconductor processing system;
Viewing the calibration wafer to obtain wafer position data;
Correcting the reference position using position data of the wafer;
A method comprising: The step of utilizing the wafer position data further comprises:
Displaying an image of the calibration wafer on a monitor;
Comparing the image of the calibration wafer with a reference image displayed on the monitor;
Determining a correction distance;
The method of claim 16 comprising: The step of utilizing the wafer position data further comprises:
Comparing image data of the calibration wafer with reference data;
Determining a correction distance;
The method of claim 16 comprising: The step of viewing the calibration wafer further comprises:
The method of claim 16, comprising passing a camera through the semiconductor processing system. The step of viewing the calibration wafer further comprises:
The method of claim 16, comprising moving a camera mounted on a plate supported on an end effector of a robot through the semiconductor processing system. The step of looking at the calibration wafer to obtain wafer position data further comprises:
The method of claim 19, comprising viewing a surface supporting the calibration wafer through the calibration wafer. The step of looking at the calibration wafer to obtain wafer position data further comprises:
20. The method of claim 19, comprising viewing an indicator of the calibration wafer position. Viewing the indicator of the position of the calibration wafer further comprises:
23. The method of claim 22, comprising identifying at least one of geometric or visual features of the calibration wafer. A method for calibrating the motion of a robot installed in a semiconductor processing system, comprising:
Moving a camera installed on the robot to a predetermined position in the semiconductor processing system;
Capturing one or more images of a substrate support by the camera;
Determining a reference motion utilized by the robot and transferring a substrate from the captured image to the substrate support;
Transferring the wafer to the substrate support using the reference motion;
Viewing with the camera the wafer mounted on the substrate support;
Capturing one or more images of a wafer by the camera;
Determining a corrected reference motion utilized by the robot and placing the substrate on the substrate support in place;
A method comprising: The step of capturing one or more images of the wafer by the camera;
The method of claim 24, comprising capturing one or more images of the substrate support viewed through the wafer. The step of capturing one or more images of the wafer by the camera;
26. The method of claim 25, comprising capturing one or more images of a wafer position indicator. Capturing the one or more images of the indicator of wafer position further comprises:
27. The method of claim 26, comprising identifying at least one of geometric or visual features of the calibration wafer. The step of moving the camera installed on the robot further comprises:
25. The method of claim 24, comprising exposing the camera to a vacuum environment. Transmitting an image captured by the camera;
Remotely receiving the captured image;
25. The method of claim 24, further comprising: A method for calibrating the motion of a robot installed in a semiconductor processing system, comprising:
Positioning the wafer in the semiconductor processing system using a stored robot motion routine;
Viewing the wafer with a camera;
Updating the stored robot motion routine using the wafer image data;
A method comprising:   32. The method of claim 30, further comprising moving the camera within a vacuum environment of the semiconductor processing system. The step of moving the camera further comprises:
32. The method of claim 31, comprising supporting the camera on a robot end effector. Transmitting an image captured by the camera;
31. The method of claim 30, further comprising remotely receiving the captured image. The step of viewing the wafer with the camera further comprises:
The method of claim 30, comprising capturing one or more images viewed through the wafer. The step of viewing the wafer with the camera further comprises:
31. The method of claim 30, comprising capturing one or more images of a wafer position indicator. Capturing the one or more images of the indicator of wafer position further comprises:
36. The method of claim 35, comprising identifying at least one of geometric or visual features of the calibration wafer.

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